Varicose Veins and DVT

The image above illustrates the anatomical and physiological differences between a normal vein and a varicose vein. Which of the following is the primary underlying pathological mechanism depicted in the varicose vein?

A 52-year-old woman from Delhi presents with a 3-year history of progressive swelling and heaviness in the left lower limb, worse at the end of the day. On examination, she has dilated, tortuous veins over the medial aspect of the thigh and calf, with mild pitting edema. Trendelenburg test is positive. Duplex ultrasound shows reflux in the greater saphenous vein (GSV) lasting >0.5 seconds. She has no history of DVT. What is the most appropriate next step in management?

A 58-year-old man from Mumbai presents with acute onset swelling, pain, and warmth in the right lower limb over the past 24 hours. He had undergone total knee replacement 10 days ago. On examination, the right calf is swollen (3 cm difference in circumference compared to left), tender, and warm. Homan's sign is positive. D-dimer is elevated at 1.2 μg/mL (normal <0.5). Compression ultrasound shows a hypoechoic, non-compressible thrombus in the popliteal vein extending into the distal femoral vein. What is the most appropriate initial management?

Which of the following is the primary pathophysiological mechanism underlying the development of primary varicose veins?

Which of the following is the most common site of origin for deep vein thrombosis in the lower limb?